1. Field of the Invention
The present invention relates to a method for determining a cell number (number of cells), a cell number determination device, a power supply device, and a program.
2. Description of Related Art
A method for configuring a battery in which one battery is configured with one-cell batteries referred to as cells by connecting a plurality of one-cell batteries in series has been widely performed. Since a voltage value of a cell unit is fixed, it is necessary to connect a plurality of cells in series in order to realize a desired voltage value by a user.
As discussed above, a voltage value of the battery that is configured by connecting a plurality of cells in series varies in accordance with the number of cells. Therefore, it is necessary that the number of cells that configure the battery must be known to adjust various types of control for the battery, including charge control, to a voltage value of the battery. For example, JP H6-205542 A (patent reference 1) discloses a battery charge control system in which a setting means for setting the number of cells is provided. The setting means for setting the number of cells in patent reference 1 is, for example, a keyboard.
JP 3331529 B (patent reference 2) discloses an electrical accumulator device and electric power system in which an abnormal battery is detected among a plurality of batteries (corresponding to cells); and the abnormal battery is shorted by electrically removing it through a relay of a switching element. In patent reference 2, although the number of cells is not set, the abnormal cell is removed when it is detected at the time of operation of the battery so that control for adjusting to the remaining number of cells is performed.
As discussed above, it is necessary for a battery configured with a plurality of cells to perform control adjustable for the number of cells. Therefore, when control for a battery is performed, a user and so on is required to set the number of cells in advance. Even though the number of cells is set in advance, an abnormality would occur in a cell while controlling the battery. In this case, it is necessary that the control is performed in accordance with the remaining number of cells from which an abnormal cell is excluded. Therefore, when the control for the battery configured with cells is performed, it is essential that the number of cells is understood before and during the control for the battery.
1. Problems of Cell Number Setting Before Control for Battery
A setting means for the number of cells is required in order to set the number of cells before control for a battery. For example, in patent reference 1, a keyboard corresponds to a cell number setting means. In a control device, it is necessary to have an input means, such as a terminal, for inputting the number of cells set at the cell number setting means. It is not preferable to provide the setting means and the input means because a configuration of the control device is complicated. For example, eight kinds of settings are required for the control device that corresponds to a first cell through an eighth cell. Therefore, three bits, i.e. three input terminals, are required. These requirements are a big barrier in terms of simplification and miniaturization of a circuit configuration when the control device is realized by an integrated circuit (IC) or the like.
2. Problems of Cell Number Detecting During Control for Battery
When control that is adjusted to the number of cells is performed by detecting the number of cells during the control for a battery, the normal number of cells is not understood at the beginning of the control. Therefore, after the control for the battery is begun, it is necessary to have processing for changing the control contents and so on. During this period, there is a problem that power supplied by the battery is temporarily stopped. In conclusion, even though the number of cells is detected during the control for the battery, it is essential to set the number of cells before the control for the battery.